Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, yet the description adds substantial context beyond them: results are capped with a true count, services ('Service — no stock') are excluded, the rule matches the dashboard chip, and Counter-use companies see day-close figures with a clear explanation of the open-trading-day skew. This is exactly the behavioral detail that prevents misreading the numbers.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads the purpose, then the row shape, capping, exclusions, the rule, and the Counter caveat. Nearly every sentence earns its place, though the density is high and the Counter sentence is long enough to be a slight drag on scanability.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema and no parameters, the description carries the full burden and discharges it: it enumerates the returned columns (sku, name, on-hand, reorder point, unit), discloses capping plus true count, and explains the accounting-timing caveat. An agent has everything needed to call and interpret it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Zero input parameters, so the baseline is 4; there is nothing to document and the description does not need to compensate. It correctly spends its words on output shape instead.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a precise verb+resource outcome: the products at or below their reorder point, framed as 'the what do I need to reorder list'. It gives the exact inclusion rule, which is enough to distinguish it from stock_level and stock_movements without opening schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The framing ('what do I need to reorder') makes the use case explicit and the disclosed rule (reorder point set AND on-hand ≤ reorder point) tells the agent exactly which products qualify. It does not explicitly name a sibling alternative or a when-not condition, so it stops short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.